Use the employer’s date as an objective while the actual eligibility, evidence and process are assessed. TN preparation and government decisions are separate steps, and an expected date is not authorization to work.
Identify the next factual decision
Ask what must be confirmed before the letter can be finalized and who controls that information. Review current procedures before booking travel. If a new employer, changed duties or a different assignment emerges, request reassessment of the arrangement. A temporary offer does not remove the need to consider the person’s immigration history or longer-term intent.
The two long items usually sit outside the employer's control: a provincial regulator or registrar issuing a letter of standing, and a credential evaluation for a degree earned outside Canada or the United States. A Canadian citizen may request TN admission at an eligible port of entry or preclearance location, or a prospective employer may file Form I-129, but neither option converts incomplete licensing or certification into permission to practise. Where the employer needs cover in the interim, that is a staffing question to be solved separately rather than a reason to compress the immigration one, and saying so early usually produces a better conversation than discovering it after a second attempt.